The effect of salinity on the interaction between microplastic polyethylene terephthalate (PET) and microalgae Spirulina sp.

The increasing use of plastic over the last few decades has had an impact of plastic pollution in aquatic ecosystems. Plastic pollutions may be in the form of microplastics either from primary or secondary sources. These microplastics will indirectly affect human health through the food chain. This research was aimed at evaluating the interaction between microplastic and microalgae that are a source of food supplements. The experiment was conducted by investigating the impact of microplastic polyethylene terephthalate (PET) on microalga Spirulina sp. cultivated in fresh water and saline water (7 ppt salinity) for 14 days. The growth rate and morphology of Spirulina sp. and PET were evaluated. The result showed that the presence of PET and salinity decreased Spirulina sp. growth rate in cultivation by 0.174 day(-1) and reduced nutrient removal rates. However, the salinity system on medium-added PET was indicated that there are influences of Spirulina sp. against PET, where PET can be degraded by Spirulina sp. in the state of water with a salinity 7 ppt. FTIR graphic seems if there is any peak declination within PET augmentation in media with 0 ppt salinization. Nonetheless, the peak augmentation happened within PET augmentation in media with 7 ppt salinity. This signifies if there is an augmentation of PET salinization can be degraded by Spirulina sp. as the polysaccharide sources. PET is resistant to degradation due to its aromatic group. Based on the results scanning electron microscope (SEM), Spirulina sp. which growth with PET had a more uneven shape compared with a control variable.

Automated summary

The study revealed that both PET and salinity can decrease the growth rate of Spirulina sp. and reduce nutrient removal rates. However, the presence of salinity in the medium with added PET demonstrated that Spirulina sp. can degrade PET, showing its potential as a source of polysaccharides.